Field of the Disclosure
The disclosure relates generally to techniques for weight loss and, more particularly, to techniques for reducing gastric volume by using a digestible or implantable activator.
Brief Description of Related Technology
Morbid obesity is associated with a significant reduction in survival, and increased risk of co-morbid conditions such as diabetes and heart disease. Often life-style modifications, dietary interventions and exercise may not be sufficient for meaningful weight loss due to a variety of factors such as noncompliance, etc. In recent years bariatric surgery, which involves reduction in gastric volume by using a variety of techniques such as gastric banding, stapling, etc., has evolved as a therapeutic option to promote weight loss. However, the surgery may require significant skill and expertise, and may be associated with considerable risk of complications, morbidity and mortality—most patients with morbid obesity carry a higher surgical risk. Furthermore, recovery may be prolonged; and the procedure is irreversible.
Considering the number of patients with morbid obesity, some researchers have proposed digestible or implantable gastric reduction devices to facilitate weight loss. The techniques have some measure of success, but there are limitations. Intragastric balloons have been proposed reducing gastric volume. Orally administered polymer-based structures that expand in the stomach in response to changes in hydration, pH levels, etc. have also been proposed.
For intragastric balloons, the techniques are invasive and thus less desirable, except in the more extreme cases. In particular, while inflatable balloons can offer internal pumping mechanisms, pressure sensors, and controlled pump release, such features make the devices overly bulky and incapable of either ingestion or passing through the intestines.
For orally administered structures, digestibility requires small devices, which are typically implemented only in a solid-phase change form. This basically means the device is formed of a polymeric outer shell and solid interior that expands in response to environment stimuli contacting that shell. Examples include polymeric formulations such as acid-sensitive, gelatin coatings and dehydration hydrophilic polymers. When ingested the polymeric coating triggers a time release expansion of the device. Unlike implantable balloon devices, the ingestible devices are passable through the pyloric valve in the stomach, but that passing is a result of a solid phase degeneration of the device, and not actively controllable after the device has been ingested into the stomach.
A few orally administrable polymer-based devices that attempt to offer some level of control functionality have been suggested. This includes controlled degradation devices having a plurality of polymer molecules that are each expandable in aqueous solution and releasably coupled through a controlled carrier. The device can selectively release any number of the polymer molecules, each of which then expands based on a solid phase interaction. The technique is limited in a number of ways. For example, polymer release is controlled based on external conditions and not based on conditions measured within the stomach. There is no ability to dynamically control the amount of expansion of each polymer molecule, in particular to controllably reduce the volume of the carrier, for example, to induce device release.